Abstract

Sybrandt Hansz Cardinael (1578-1647) was a widely respected Amsterdam reckonmaster and geometer in the early seventeenth century. Also in the domains of navigation, astronomy, gauging,and geodesy he gained much distinction. In the course of time his reputation fell into oblivion. In the present article his career is being outlined also on the basis of new archival material, and an attempt is made at characterizing his work in the light of his personality. Cardinael was a native of Harlingen and mainly moved in Mennonite circles. He was closely associated with well-known families, such as Savry and Bruyningh, and was married to the daughter of another Mennonite reckonmaster, Lieven Panten. Especially notable are his serving on a committee concerning the determination of longitude and his appointment to Coster's Academy. Moreover, he was responsible for various publications. The most important one is the Hondert Geometische Questien (A Hundred Geometrical Problems) published in 1612. The book had a wide audience both at home and abroad. Its charm and attraction lie mainly in the purely geometrical manner in which Cardinael solves the geometrical and geodetic problems of his time. His conservative attitude prevented him from using new techniques such as algebra (also called Regula Coss), which were to become common property with Descartes. In an appendix his mathematical working-methods will be entered into. It will be shown how Cardinael, often in an ingenious way, makes use of traditional application of surfaces (which dates back to Euclid) and geometrical algebra in order to arrive at his mathematical solutions